JP4087590B2 - Wood type golf club head - Google Patents

Description

【００５０】
テストの結果、実施例のものは比較例に比べると、強度、反発性能、フィーリングとも良好な結果を示していることが確認できた。特に熱間鍛造、空冷の処理を２階繰り返して行った実施例７、８については、非常に高い耐久性能と反発係数とを実現していることが確認し得た。
【００５１】
【発明の効果】
以上説明したように、請求項１ないし３記載の発明では、フェース面の巾、高さを限定するとともに、フェース中心を含む中央厚肉部とその外側の周辺薄肉部の厚さの分布を実験により確かめ得た最適なものとしたことによって、耐久性能を損ねることなく反発性能を向上することができる。
【００５２】
また請求項１記載の発明において、フェース部材に特定のチタン合金を用いるとともに、その加工法を限定することによって、さらに反発係数と耐久性能とをバランス良く向上することができる。
【図面の簡単な説明】
【図１】本発明の実施形態を示すヘッドの斜視図である。
【図２】その分解斜視図である。
【図３】基準状態のヘッドの正面図である。
【図４】その平面図である。
【図５】（Ａ）〜（Ｃ）はフェース面の周縁を説明する線図である。
【図６】ヘッドのフェース中心を通る垂直断面図である。
【図７】ヘッドのフェース中心を通る水平断面図である。
【図８】垂直断面における基部の厚さを示すグラフである。
【図９】水平断面における基部の厚さを示すグラフである。
【図１０】基部の厚さの等高線近似図である。
【図１１】基部の端縁を説明する拡大断面図である。
【符号の説明】
１ ウッド型ゴルフクラブヘッド
１Ａ フェース部材
１Ｂ ヘッド本体
２ フェース部
３ クラウン部
４ ソール部
５ サイド部
６ ネック
７ 基部
９ 延長部
９ａ クラウン側の延長部
９ｂ ソール側の延長部
９ｃ トウ側の延長部
９ｄ ヒール側の延長部
Ｆ フェース面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wood type golf club head capable of improving resilience performance without impairing durability.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, in a wood type golf club head, in order to increase the flight distance of a hit ball, it has been proposed to improve the resilience performance at the time of collision with a ball. Specifically, a method of improving the material of the face part, a method of designing the thickness of each part of the face part, etc. (more specifically, making the face part thinner) are known.
[0003]
However, when the thickness of the face part is uniformly reduced, there is a problem that the strength of the face part itself is lowered and the durability performance is remarkably deteriorated. In order to remedy such problems, the center area of the face part where the ball frequently collides is thickened, and the peripheral area where there is little chance of collision with the ball is thinned, so high resilience performance without causing strength reduction For example, Japanese Patent No. 3064905 proposes to exhibit the above.
[0004]
However, none of the conventional proposals has a detailed suggestion about the specific thickness, shape, etc. of the face portion. Further, as a result of intensive studies, the inventors have found that the rebound performance and durability of the head can be further improved in a well-balanced manner by reviewing the material of the face member and the processing process thereof.
[0005]
As described above, the present invention provides a wood-type golf club head capable of improving the resilience performance without impairing the durability, based on specifically limiting the shape, thickness, etc. of the face portion. It is aimed.
[0006]
[Means for Solving the Problems]
  According to the first aspect of the present invention, a face member having a face surface for hitting a ball and a neck portion to which the face member is fixed and to which a shaft is attached are integrally provided.Moreover, it is integrally molded by the lost wax precision casting method.From the head bodyA two-piece golf club head,
  The face member has a hook shape having a base portion forming the face surface and an extension portion extending from the back surface of the base portion to the rear of the head,
  The extension includes an extension on the crown side that forms part of the crown, an extension on the sole that forms part of the sole, and a toe that forms part of the toe side of the side. A side extension portion and a heel side extension portion forming a part of the heel side portion of the side portion 5.,
  The extension part on the crown part side has a recess in which the neck part of the head body fits.,
  AndThe face height, which is the maximum length in the vertical direction of the face surface, is 40 to 60 mm and the maximum length in the horizontal direction of the face surface in a reference state in which the lie angle and face angle are placed on a horizontal plane. The face width is 70 to 110 mm,
  In addition, the base portion includes a center thick portion including a face center at which the intermediate positions of the face height and face width intersect and a thickness of 2.5 to 2.9 mm, and an annular shape surrounding the center thick portion. And a peripheral thin wall portion having a thickness of 1.9 to 2.3 mm,
  In the vertical cross section passing through the center of the face, the length of the central thick part is 10 to 30 mm, and the length of the peripheral thin part is 3 to 10 mm from the edge of the base,
  Moreover, in a horizontal cross section passing through the center of the face, the length of the central thick part is 30 to 60 mm, and the length of the peripheral thin part is 3 to 20 mm from the edge of the base,
  Moreover, the face member is made of Ti-4.5Al-3V-2Mo-2Fe,AndAfter being hot forged at a temperature of 800 to 880 ° C. and then being formed of a hot forged product cooled in an atmosphere in a temperature range of 0 to 100 ° C., the base and the extension are configured integrally,
  The cooled hot forged product is hot-forged again at a temperature of 800 to 880 ° C. and cooled in an atmosphere of 0 to 100 ° C. for two cycles.This is a wood type golf club head.
[0007]
  In the invention according to claim 2, the thickness of the central thick part is 2.6 to 2.8 mm and the thickness of the peripheral thin part is 1.9 to 2.1 mm. The length of the central thick part is 10 to 24 mm, and the length of the peripheral thin part is 5 to 10 mm from the edge of the back face part.The invention according to claim 3 is characterized in that:In the horizontal cross section, the length of the central thick part is 40 to 60 mm and the length of the peripheral thin part is 5 to 20 mm from the edge of the base.Features.
[0008]
  AlsoClaim 4The invention is characterized in that the coefficient of restitution is 0.840 or more.The
[0009]
  Note that the “rebound coefficient” is the U.S. S. G. A. Measured in accordance with the Procedure for Measureing the Velocity Ratio of a Club Head for Conformance to Rule 4-1e, Revision 2 (February 8, 1999)The
[0010]
  Specifically, a golf ball is launched using a ball launching device, is caused to collide with a sweet spot on the face portion of the head placed without being fixed on the pedestal, and an incident velocity Vi and a rebound velocity immediately before the golf ball collides. Measure Vo. The restitution coefficient e was calculated from the following equation, where Vi was the incident speed of the golf ball, Vo was the rebound speed, M was the head mass, and m was the average mass of the golf ball.
      (Vo / Vi) = (eM−m) / (M + m)
  The distance from the golf ball launch port to the face is 55 inches, and the ball is 5 inches from the sweet spot position of the head. mm Collide with the face surface at a position that is not further away and at a right angle. The golf ball uses Titleist Pinnacle Gold, and the initial ball speed is set to 160 feet ± 0.5 feet.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a wood type golf club head according to an embodiment of the present invention, FIG. 2 is an exploded perspective view thereof, FIG. 3 is a front view of a reference state, and FIG.
[0012]
In the figure, a wood type golf club head (hereinafter, simply referred to as “head”) 1 is connected to a face portion 2 having a face surface F hitting a ball as a surface and an upper edge Ea of the face surface F. Further, the crown portion 3 that forms the upper surface of the head, the sole portion 4 that continues to the lower edge Eb of the face surface F and forms the bottom surface of the head, and the heel from the toe side edge Ec of the face surface between the crown portion 3 and the sole portion 4 Examples include a side portion 5 that forms the side surface of the head extending to the side edge Ed, and a neck portion 6 to which a shaft (not shown) is attached. The head 1 is made of a metal material and has a hollow shape having a hollow portion i therein.
[0013]
  As shown in an exploded view in FIG. 2, the head 1 of this embodiment includes a face member 1 </ b> A having the face surface F, and a head body that is fixed to the face member 1 </ b> A by welding in this example to form the head 1. 1B, a so-called two-piece structure constructed by joining these two partsHave.Such a two-piece structure head 1 can reduce the number of welding points and reduce work processes and improve productivity as compared with a three-piece structure head, and also suppress variations in various dimensions and angles of the head. Therefore, a highly accurate head can be provided.
[0014]
The head main body 1B includes, for example, a crown base portion 14 that forms a main portion of the crown portion 3, a sole base portion 15 that forms a main portion of the sole portion 4, and a connection between the crown base portion 14 and the sole base portion 15. In addition, the side base portion 16 that forms the periphery of the head and the neck portion 6 are integrally provided, and the front surface portion has an opening O in which the face member 1A is disposed. For example, a claw piece 17 or the like that can temporarily hold the face member 12 through a gap is appropriately provided in the opening O, and workability when welding both members can be improved. The neck portion 6 has a cylindrical body so that a circular shaft insertion hole 6a is formed therein. When the head 1 is tilted to a specified lie angle, the shaft center line CL of the shaft insertion hole 6a is formed. Can be the standard.
[0015]
  The head body 1B can be formed of various metal materials such as aluminum alloy, titanium, titanium alloy, and stainless steel. In this example, Ti-6Al-4V, which is an α + β type titanium alloy, is employed, and the respective parts are integrally formed by a lost wax precision casting method. For this reason, the neck portion 6 can be accurately formed with respect to the sole base portion 15, which is useful for reducing variations such as lie angles and improving accuracy.One.
[0016]
In this example, the face member 1A includes a base portion 7 that forms the face surface F and an extension portion 9 that extends from the back surface of the base portion to the back of the head (back face side). The extension portion 9 is, for example, about 7 to 30 mm from the periphery E of the face surface F (referred to as the periphery E including the upper edge Ea, the lower edge Eb, the toe side edge Ec, and the heel side edge Ed). It has a length D and terminates.
[0017]
  In the present example, the base portion 7 has a preferred mode of forming substantially the entire area of the face surface 2. The extension 9TheA crown portion side extension portion 9a that forms a part of the round portion 3, a sole portion side extension portion 9b that forms a portion of the sole portion 4, and a toe portion that forms a part of the toe side portion of the side portion 5. Side extension portion 9c and a heel side extension portion 9d forming a part of the heel side portion of the side portion 5. The base 7 and the extension 9 are not joined by welding or the like,From hot forgingIt is constructed integrally. Thereby, the face member 1A is formed in a substantially bowl shape.As obvious from FIG. 2, the extension 9a on the crown side isNeck portion side portion of the face member 1AButThe neck portion 6 provided in the head main body 1B fits into the recess. That is, the head main body 1B integrally includes a neck portion 6 to which a shaft is attached, and the face member 1A includes a concave portion in which the neck portion 6 is fitted.
[0018]
  In such a head 1, a welded portion joined to the peripheral edge E of the face surface F by welding is not formed. When welding is performed at the peripheral edge E of the face surface F, not only the workability is poor, but also a weld bead (not shown) that cannot be polished remains on the hollow portion i side of the head 1, and the thickness of the portion increases. There is a tendency to reduce the resilience performance of the head 1 due to high rigidity. FIn the head 1, by providing the extension portion 9, the welded portion between the face member 1A and the head main body portion 1B can be moved away from the peripheral edge E of the face surface F to the rear of the head. Accordingly, it is possible to suppress a decrease in the resilience performance of the head.
[0019]
From the above viewpoint, it is particularly preferable that the length D of the extension 9 is 8 mm or more, and more preferably 10 mm or more. On the other hand, if the length D of the extension portion 9 is too large, it becomes difficult to form the face member 12 by plastic working such as forging or pressing, which tends to reduce productivity. From this point of view, the length D of the extension 9 is preferably 30 mm or less, particularly preferably 25 mm or less, more preferably 20 mm or less in combination with any one of the lower limit values.
[0020]
Further, as shown in FIGS. 3 and 4, the head 1 has a face height h that is the maximum length in the vertical direction of the face surface F in a reference state where the head 1 is placed on the horizontal plane HP with a specified lie angle β and face angle δ. Is set to 40 to 60 mm, and the face width W which is the maximum horizontal length of the face surface F is set to 70 to 110 mm.
[0021]
The head 1 has a lie angle β and a hook angle δ determined in advance. In this specification, the reference state of the head 1 is set to the lie angle and the face angle. When the head 1 is set to the lie angle β, the shaft center line CL of the shaft insertion hole 6a is arranged in the vertical plane VP1 as shown in FIG. 4 and is inclined at the lie angle β with respect to the horizontal plane HP. Further, after setting the lie angle β, the face angle δ is set such that the horizontal tangent N passing through the center of gravity FG of the face surface by rotating the head 1 around the axis center line CL of the shaft insertion hole 6a becomes the face angle δ. Fit together. The face width is measured as a length in a direction perpendicular to the vertical plane VP1 as shown in FIG.
[0022]
If the face width W is less than 70 mm, the amount of deflection at the time of ball collision becomes small, and sufficient resilience performance cannot be obtained. Conversely, if it exceeds 110 mm, the amount of deflection increases and the resilience performance improves, but there is a problem that the load on the peripheral edge of the face surface F increases and the durability performance deteriorates. More preferably, the face width W is 90 to 105 mm. On the other hand, when the face height h is less than 40 mm, the amount of deflection becomes small like the face width, so that sufficient resilience performance cannot be obtained. Conversely, if it exceeds 60 mm, the resilience performance can be improved, but there is a problem that the durability performance is lowered. More preferably, the face height h is set to 45 to 55 mm.
[0023]
  The face width W and the face height h are both measured with respect to the peripheral edge E of the face surface F. When the edge E can be substantially specified by a ridge line, the rim line is used as the ridge line. However, the portion where the ridge line is not clear is shown in FIG. 5A with respect to the face surface F passing through the sweet spot point SS. Tangent (FIG.Then, only four of A to D are illustrated.) R is drawn, and as shown in FIGS. 5B and 5C, an inclined line extending backward from the head at an angle of 45 ° with respect to each tangent line R. It is also possible to draw U and continuously determine the intersection where the inclined line U intersects the head surface. Reference numeral G denotes a head center of gravity, and K denotes a normal line drawn from the head center of gravity G to the face surface F. The intersection of the normal line K and the face surface F is displayed as a sweet spot point SS.
[0024]
The face surface F has a surface area of 3000 to 5500 mm while satisfying the requirements of the face height h and face width W.², More preferably 3500-5000 mm²Is desirable. The surface area is 3000mm²Less than or 5500mm²If it is larger than the above range, the shape of the face surface becomes distorted, and it tends to be difficult to improve the resilience performance and durability performance in a balanced manner.
[0025]
Further, as shown in FIG. 3, the base portion 7 includes a face center FC at which the intermediate positions P3 and P2 of the face height h and the face width W intersect, and has a thickness Tc of 2.5 to 2.9 mm. A central thick portion 7a and a peripheral thin portion 7b having an annular shape surrounding the central thick portion 7a and a thickness Te of 1.9 to 2.3 mm are included. 3 and 6, in the vertical cross section VP2 passing through the face center FC, the length Lc1 of the central thick portion 7a is 10 to 30 mm and the length Le1 of the peripheral thin portion 7b is the base portion 7. Further, as shown in FIG. 7, in the horizontal section HP2 passing through the face center FC, the length Lc2 of the central thick portion 7a is 30 to 60 mm and the length of the peripheral thin portion 7b. The length Le2 is set to 3 to 20 mm from the edge 7e of the base portion 7. FIG. 8 is a graph showing the thickness of the base portion 7 in the vertical cross section, where the horizontal axis indicates the position in the height direction with respect to the face center FC, and the vertical axis indicates the thickness of the base portion. Similarly, FIG. 9 shows a graph showing the thickness of the base in the horizontal section.
[0026]
In the present invention, the size of the face surface F is limited as described above, and various experiments are attempted on the basis of the shape of the limited face surface F, and the resilience performance and durability can be improved in a balanced manner. The optimum thickness distribution has been found. That is, since the central thick part 7a is a part that frequently collides with the ball, it is necessary to maintain a sufficient strength. For this reason, it is important to have a predetermined thickness and a predetermined region. It becomes. On the other hand, if the thickness of the central thick portion 7a is too large and the area occupied by the central thick portion 7a is too large, the resilience performance is deteriorated and it is difficult to improve the flight distance of the hit ball.
[0027]
Therefore, in the present invention, the thickness Tc1 of the central thick portion 7a is set to 2.5 to 2.9 mm, and more preferably set to 2.6 to 2.8 mm. If it is less than 2.5 mm, the durability performance is insufficient, and if it exceeds 2.9 mm, the resilience performance deteriorates. Although the central thick part 7a of this example shows what was formed by substantially constant thickness, thickness can also be changed in the said numerical range. When the thickness of the base portion 7 is measured, it is performed in a portion without the face groove.
[0028]
Further, in this example, as shown in FIG. 3, the central thick portion 7a has a horizontally long oval shape along the shape of the face surface F, and needs to have a length Lc1 of 10 to 30 mm in the vertical section. It is necessary that the horizontal section has a length Lc2 of 30 to 60 mm. If the length Lc1 of the central thick part 7a is less than 10 mm or the length Lc2 is less than 30 mm, the strength of the base part 7 is difficult to obtain, and there is a tendency that satisfactory durability performance cannot be obtained. If the length Lc1 is greater than 30 mm or the length Lc2 is greater than 60 mm, the rigidity of the base portion becomes so large that the resilience performance cannot be improved. The length Lc1 is preferably 10 to 24 mm, more preferably 14 to 24 mm. The length Lc2 is preferably 40 to 60 mm. Although not particularly limited, the ratio (Lc1 / Lc2) of the lengths Lc1 and Lc2 of the central thick part 7a is 0.25 to 0.60, more preferably about 0.35 to 0.50. Is desirable.
[0029]
Further, since the peripheral thin portion 7b has less chance of directly colliding with the ball, it can be made thinner than the central thick portion 7a, and the base 7 is sufficiently bent at the time of hitting to improve the resilience performance. From such a viewpoint, it is necessary for the peripheral thin portion 7b to set the thickness Te to 1.9 to 2.3 mm, but it is more preferable to set the thickness Te to 1.9 to 2.1 mm. desirable. If the thickness is less than 1.9 mm, the durability performance is deteriorated although the resilience performance is excellent. Conversely, if the thickness exceeds 2.3 mm, the peripheral thin portion 7b becomes difficult to bend, and improvement in the resilience performance cannot be expected. In this example, the peripheral thin portion 7b is formed with a substantially constant thickness, but it can be configured so as to vary within the above numerical range.
[0030]
Further, since the peripheral thin portion 7b is small in thickness, if the area is increased, the durability tends to be impaired, and conversely, even if it is too small, it is difficult to sufficiently bend the head when hitting and the resilience performance is improved. It becomes difficult. From this point of view, the length Le1 of the peripheral thin wall portion 7b in the vertical cross section is 3 to 10 mm from the end edge 7e of the base portion 7 (the length from the end edge 7e is 3 to 10 mm, hereinafter the same meaning) In addition, in the horizontal section, the length Le2 of the peripheral thin portion 7b is set to 3 to 20 mm from the end edge 7e of the base portion 7.
[0031]
When the length Le1 or Le2 of the peripheral thin wall portion 7b is less than 3 mm, the amount of bending of the base portion 7 is reduced and improvement in resilience performance cannot be expected. Conversely, when the length Le1 is greater than 10 mm, Or when the said length Le2 is larger than 20 mm, there exists a tendency for the durable performance of the base part 7 to fall. More preferably, the length Le1 of the peripheral thin portion 7b is 5 to 10 mm. Further, the length Le2 of the peripheral thin portion 7b is more preferably 5 to 20 mm, and further preferably 10 to 20 mm.
[0032]
The length Le1 of the peripheral thin portion 7b may be the same on the crown portion side and the sole portion side, or may be different. In general, the rigidity on the crown side is lower than that on the sole side. Therefore, by changing the length Le1 of the peripheral thin portion 7b between the crown portion side and the sole portion side, the rigidity can be controlled, and the deformation of the face portion at the time of hitting can be improved with a better balance.
[0033]
Similarly, the length Le2 of the peripheral thin portion 7b may be the same on the toe side and the heel side, or may be different. Generally, the toe side is less rigid than the heel side. Accordingly, by making the length Le2 of the peripheral thin portion 7b different between the toe side and the heel side, the rigidity can be controlled, and the deformation of the face portion at the time of hitting can be improved with a better balance.
[0034]
In addition, the edge 7e of the base 7 in each of the cross sections, as shown in an enlarged view in FIG. 11, is the base 7 and the extension 9 on the inner surface facing the hollow part i of the head 1 (in FIG. 11, the extension 9a on the crown side). ) Is defined as the end point X2 of the joint arc R that smoothly connects the end point X1 on the extension 9 side and the end point X2 on the base side.
[0035]
The base portion 7 includes an annular thickness changing portion 7c between the central thick portion 7a and the peripheral thin portion 7b. The annular thickness changing portion 7c has a thickness that gradually and continuously decreases toward the peripheral edge E of the face surface F. Including. In this way, by smoothly changing the thickness between the central thick part 7a and the peripheral thin part 7b, it is possible to prevent the occurrence of a rigidity step and to suppress the stress concentration at the time of hitting, and to further improve the durability of the face part 2. Can improve the performance. In addition, in FIG. 10, the contour map which shows the change of the thickness of the base 7 is shown for reference. The thickness of each part is obtained by performing an approximation process using a weighted least square method.
[0036]
The head having the above-described configuration can improve the resilience performance and improve the flight distance of the hit ball without impairing the durability performance by limiting the thickness of the face portion 2 in various ways. More specifically, the coefficient of restitution can be increased to 0.830 or more, more preferably 0.840 or more, and even more preferably about 0.860 to 0.870.
[0037]
Further, the inventors have further researched and found that the effect can be further enhanced by adopting a specific processing method for the face member 1A. Specifically, the face member 1A is made of Ti-4.5Al-3V-2Mo-2Fe titanium alloy, hot forged at a temperature of 800 to 880 ° C., and then cooled at room temperature. It has been found that using a forged product is effective.
[0038]
The face member 1A made of such a hot forged product can have a denser crystal structure and higher strength than a cast product, and can increase the surface hardness. This makes it difficult to generate initial cracks such as fine cracks, which are the main causes of deterioration of the durability performance of the face surface, and this can greatly improve the durability performance.
[0039]
The reason why Ti-4.5Al-3V-2Mo-2Fe, which is one of α + β type titanium alloys, was adopted as the titanium alloy is that this material best meets the object of the present invention. That is, when α-type titanium, for example, pure titanium, is employed, it is difficult to form the face member 1A that has a small tensile strength and can withstand the impact force upon hitting. Also, when β-type titanium is used, when forging a complex-shaped face member 1A integrally having an extension 9 as in this example, it must be processed after being held at a relatively high temperature for a certain period of time. In this case, there is a problem that the crystal grains become coarse and acicular, and the strength, toughness, and fatigue strength tend to decrease. Examples of the α + β type titanium alloy include Ti-6Al-4V (6-4 titanium), Ti-3Al-2.5V, etc. The former generally has poor workability, and the face member 1A having a complicated shape is generally used. In the case of forging, it is necessary to heat to 900 ° C. or higher, which increases the cost during processing and facilitates surface oxidation, and this oxide layer is liable to cause fatigue cracks. Is better than Ti-6Al-4V, but is not preferable because the absolute strength of the material itself is insufficient.
[0040]
Moreover, the temperature of the said hot forging means the temperature of material itself at the time of forging. Moreover, when the temperature at the time of this hot forging becomes lower than 800 ° C., the plastic workability of Ti-4.5Al-3V-2Mo-2Fe is lowered, so that the fatigue of the mold or the like is large and the productivity tends to deteriorate. On the other hand, if the temperature during hot forging is higher than 880 ° C., surface oxidation during forging becomes remarkable and durability deteriorates. Further, since the β transformation point of the titanium alloy is about 890 ° C., when the processing is performed at a temperature higher than this, the entire crystal structure is transformed into the β phase, and then needle-like α crystals are precipitated in the β crystal by cooling. To do. Since the β crystal is 50 times larger than the pro-eutectoid α crystal, the cracks are more likely to propagate, the fatigue characteristics deteriorate, the material hardness increases excessively, and the face becomes brittle and prone to cracking. The strength of the member 1A is likely to be insufficient, and the intended purpose of the present invention cannot be achieved. From such a viewpoint, the temperature during the hot forging is preferably 800 to 850 ° C, more preferably 820 to 830 ° C.
[0041]
In hot forging, the face member 1A is obtained by heating the massive titanium alloy material such as a plate material or a round bar to the above temperature and hitting or pressing it with a hammer or a press die. As described above, the face member 1A processed by forging is preferable in that a dense crystal structure can be obtained as compared with casting, the strength of the material can be improved, and the material is accompanied by a large plastic deformation. Therefore, the U-shaped or substantially bowl-shaped face member 1A can be easily formed using such large plastic deformation. In particular, in the case of hot forging in which the titanium alloy is heated to the temperature and processed, the ductility of the material is further improved, which further helps to improve the workability. Forming methods in forging include, for example, various types such as free forging, die forging (including open die, closed die or semi-closed die), high speed forging or isothermal forging, and cause compression plastic deformation of the material. Any appropriate one can be used. Preferably, it is desirable to use a closed die forging method in which an oxide film (scale) is unlikely to be formed on the surface of the shaped material obtained by forging.
[0042]
The face member 1A needs to be cooled at room temperature after being formed by the hot forging. The room temperature means a temperature range of 0 to 100 ° C., more preferably 10 to 50 ° C. After hot forging, the face member 1A is taken out from the processing furnace and air-cooled (naturally left) in the temperature atmosphere. In addition, hot forging is performed in a high-temperature processing furnace, and in the past, it was allowed to stand and gradually cool in the furnace, but this method has a long aging effect because the material is held at a high temperature. It is not preferable because the material hardness is large and the hitting feeling tends to deteriorate. In addition, although rapid cooling such as water cooling is conceivable, this method has a problem that residual stress during hot forging increases and distortion is likely to occur during welding, resulting in unstable shape. It is also preferable to apply an appropriate means for preventing surface oxidation during air cooling.
[0043]
  Also,In the present inventionThen, hot forging is performed at the above temperature, and then air cooling is performed at room temperature, and after cooling, hot forging is performed again at a temperature of 800 to 880 ° C. and natural cooling is performed at room temperature, that is, two cycles of processing. TheDo.In order to process a complicated shape and thickness with high accuracy, dimensional accuracy can be further improved by processing in such two cycles. In addition, when considering mass productivity, good and bad by controlling the shape and thickness affects the man-hours in the post-process after forging, but in two cycles the man-hours in this post-process can be reduced, resulting in machining This is preferable in terms of time reduction and accuracy improvement.
[0044]
  The embodiment of the present invention has been described above.ButThe length can be different between the extension 9a on the round side and the extension 9b on the sole side.
[0045]
【Example】
In order to confirm the effect of the present invention, a wood type golf club head (# 1: driver) according to the specifications shown in Table 1 was prototyped and various tests were performed. For the face member, Ti-4.5Al-3V-2Mo-2Fe (hereinafter referred to as SP700; α + β type titanium alloy manufactured by Nippon Steel Pipe Co., Ltd. and having a β transformation point of 890 ° C.) and Ti-6Al— 4V (β transformation point 990 ° C.) was used. The processing conditions were as shown in Table 1. The head main body was unified to Ti-6Al-4V, and the face member was welded thereto by TIG welding. The test method is as follows.
[0046]
<Durability test 1>
Each sample head is fitted with the same shaft made of FRP to produce a wood-type golf club, and the club is attached to a swing robot and adjusted so that the head speed is 51 m / s. Each club was hit with 3000 balls, and the number of hit balls when the face portion was damaged was examined. Those that were not damaged were evaluated as “OK”.
[0047]
<Endurance test 2>
The head speed was set to 54 m / s, and a test similar to the above was performed.
[0048]
<Restitution coefficient>
U.S. S. G. A. The procedure for Measureing the Velocity Ratio of a Club Head for Conformance to Rule 4-1e, Revision 2 (February 8, 1999). The larger the value, the better the resilience performance.
Table 1 shows the test results.
[0049]
[Table 1]

[0050]
As a result of the test, it was confirmed that the examples had good results in strength, resilience performance, and feeling compared to the comparative examples. In particular, in Examples 7 and 8 in which hot forging and air cooling were repeated on the second floor, it was confirmed that very high durability performance and a coefficient of restitution were realized.
[0051]
【The invention's effect】
As described above, in the inventions according to claims 1 to 3, the width and height of the face surface are limited, and the thickness distribution of the central thick part including the center of the face and the peripheral thin part on the outside thereof is tested. As a result, the rebound performance can be improved without impairing the durability performance.
[0052]
  In the invention of claim 1,By using a specific titanium alloy for the face member and limiting its processing method, the coefficient of restitution and the durability can be further improved in a balanced manner.
[Brief description of the drawings]
FIG. 1 is a perspective view of a head showing an embodiment of the present invention.
FIG. 2 is an exploded perspective view thereof.
FIG. 3 is a front view of the head in a reference state.
FIG. 4 is a plan view thereof.
FIGS. 5A to 5C are diagrams illustrating the periphery of the face surface.
FIG. 6 is a vertical sectional view passing through the center of the face of the head.
FIG. 7 is a horizontal sectional view passing through the center of the face of the head.
FIG. 8 is a graph showing the thickness of the base in a vertical cross section.
FIG. 9 is a graph showing the thickness of the base in a horizontal section.
FIG. 10 is a contour-line approximation of the thickness of the base.
FIG. 11 is an enlarged cross-sectional view illustrating an edge of a base portion.
[Explanation of symbols]
1 Wood type golf club head
1A Face member
1B Head body
2 Face part
3 Crown
4 Sole part
5 Side part
6 neck
7 base
9 Extension
9a Crown side extension
9b Sole side extension
9c Toe side extension
9d Heel extension
F Face side

Claims (4)

A face member having a face surface for hitting the ball, two-piece structure ing from a head body which is integrally molded by the face member fixed to and comprises integrally a neck portion in which the shaft is mounted Moreover Precision Casting Method Golf club head,
The face member has a hook shape having a base part that forms the face surface and an extension part that extends from the back surface of the base part to the rear of the head,
The extension includes a crown-side extension that forms part of the crown, a sole-side extension that forms part of the sole, and a toe that forms part of the toe-side part of the side. A side extension and a heel side extension that forms part of the heel side portion of the side portion 5 ;
The extension part on the crown part side includes a recess in which the neck part of the head body fits ,
In a reference state in which the lie angle and face angle are set on a horizontal plane, the face height, which is the maximum vertical length of the face surface, is 40 to 60 mm, and the horizontal maximum length of the face surface is A certain face width is 70 to 110 mm,
In addition, the base portion includes a center thick portion including a face center at which the intermediate positions of the face height and face width intersect and a thickness of 2.5 to 2.9 mm, and an annular shape surrounding the center thick portion. And a peripheral thin wall portion having a thickness of 1.9 to 2.3 mm,
In the vertical cross section passing through the center of the face, the length of the central thick part is 10 to 30 mm, and the length of the peripheral thin part is 3 to 10 mm from the edge of the base,
Moreover, in a horizontal cross section passing through the center of the face, the length of the central thick part is 30 to 60 mm, and the length of the peripheral thin part is 3 to 20 mm from the edge of the base,
Thermal Moreover the face member is made of a Ti-4.5Al-3V-2Mo- 2Fe, and after being hot-forged at a temperature of eight hundred to eight hundred eighty ° C., cooled in an atmosphere of a temperature range of 0 to 100 ° C. The base portion and the extension portion are configured integrally by being made of a forged product,
Wood-type golf, wherein the cooled hot forged product is hot-forged again at a temperature of 800 to 880 ° C. and is subjected to two-cycle processing in which it is cooled in an atmosphere in a temperature range of 0 to 100 ° C. Club head. The central thick part has a thickness of 2.6 to 2.8 mm and the peripheral thin part has a thickness of 1.9 to 2.1 mm.
2. The golf club head according to claim 1, wherein, in the vertical cross section, the length of the central thick portion is 10 to 24 mm and the length of the peripheral thin portion is 5 to 10 mm from the edge of the base portion. The wood according to claim 1 or 2, wherein, in the horizontal section, the length of the central thick part is 40 to 60 mm and the length of the peripheral thin part is 5 to 20 mm from the edge of the base part. Type golf club head. 4. The wood type golf club head according to claim 1, wherein the coefficient of restitution is 0.840 or more .

Images